Containers for molten metal

ABSTRACT

Means for controlling the flow of molten metal through an orifice in a container comprises a sleeve insertable into the orifice from outside the container and located within the orifice, and means adapted to move the sleeve axially with respect to the orifice, the sleeve being closed at its end towards the inside of the container and having one or more inlet holes in the wall of the sleeve at a point approaching the closed end of the sleeve communicating with an axial bore through the sleeve, the sleeve being movable from a first position in which the closed end of the sleeve is co-planar with the inside face of the part of the container containing the orifice, with the inlet holes lying within and being closed by the orifice, to a second position where the inlet holes are exposed to the inside face of the container.

United States Patent [191 Lee et al.-

[ Apr. 9, 1974 1 CONTAINERS FOR MOLTEN NIETAL [73] Assignee: J. & J.Dyson Limited, Sheffield,

England 22 Filed: Mar. 30, 1973 21 Appl. No.: 346,458

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS403,167 6/1966 Switzerland 164/337 Primary Examinr-Gerald A. DostAttorney, Agent, or FirmLowe, King and Price [5 7] ABSTRACT Means forcontrolling the flow of molten metal through an orifice in a containercomprises a sleeve insertable into the orifice from outside thecontainer and located within the orifice, and means adapted to move thesleeve axially with respect to the orifice, the sleeve being closed atits end towards the inside of the container and having one or more inletholes in the wall of the sleeve at a point approaching the closed end ofthe sleeve communicating with an axial bore through the sleeve, thesleeve being movable from a first position in which the closed end ofthe sleeve is co-planar with the inside face of the part of thecontainer containing the orifice, with the inlet holes lying within andbeing closed by the orifice, to a second position where the inlet holesare exposed to the inside face of the container.

15 Claims, 5 Drawing Figures PATENTEDA R 91974 I 3802683 SHEET 1 UF 3 1CONTAINERS FOR MOLTEN METAL This invention relates to containers formolten metal, e.g., ladles, and is particularly concerned with means forcontrolling the flow of molten metal from such containers.

Hitherto the control of the flow of molten metal from, e.g., a ladle ortundish has for many years been effected by a so-called stopper-rodsystem involving the introduction in the ladle of a stopper secured to arod, the stopper normally seating on a correspondingly shaped nozzlesecured in the opening from the ladle. Such systems, however, haveseveral fundamental disadvantages such as the improper alignment thatfrequently occurs between the stopper and nozzle caused by distortion ofthe rod due to the heating effect caused by the molten metal throughwhich the rod must pass. Therefore, not only are such systemsdisadvantageous because of the need for an operative to enter a ladle toensure correct initial seating of the stopper on the nozzle, impropershut-off during-the course of teeming frequently occurs by virtue of thedistortion of the rod and by the wear that takes place on the stopperand the nozzle caused particularly by the erosion effect of the flowingmolten metal.

In an attempt to avoid certain disadvantages of stopper-rodconstructions, attempts have been made to eliminate the need to have astopper-rod by providing mechanism capable of activating a stopper fromoutside the ladle. Such systems, however, retain the disadvantagescaused by wear on the nozzle and the stopper leading to imperfectshut-off and still call for the re placement of the stopper from insidethe ladle for otherwise the whole bottom assembly requires to bereplaced. ln addition to the above the very nature of the seatingbetween the nozzle and the stopper is such as to provide a well in thebottom of the ladle in which molten metal can freeze thereby causingsticking on the nozzle of the stopper.

In an attempt to obviate all the above disadvantages there has beenrecent development of so-called sliding gate valves which are capable ofapplication to a ladle and operation from outside a ladle. However,because the shut-off point is outside the ladle, the orifice through theladle bottom lining provides an area where molten metal can freeze andit has frequently been found necessary to melt moltenmetal frozen in theorifice after opening of the valve, e.g., by the application of anoxygen lance.

According to the present invention, means for controlling the flow ofmolten metal from a container comprises a sleeve located within anorifice in the container and means adapted to move the sleeve relativeto the orifice, the sleeve being closed at its end towards the inside ofthe container and open at its opposite end and there being one or moreinlet holes in the wall of the sleeve at a point approaching the closedend of the sleeve communicating with an axial bore through the sleeve,the sleeve being such as to be capable of insertion into the orificefrom outside the container, and the relative movement between the sleeveand the orifice being such as to move the sleeve from a first positionin which the closed end of the sleeve is co-planar with the inside faceof the part of the container containing the orifice with the inlet holeslying within and being closed by the orifice to a second position Wherethe inlet holes are exposed to the inside of the container.

Thus, from closed position, i.e. the position in which molten metalcannot flow from the container by virtue of the inlet holes lying withinand being closed by the wall of the orifice, the sleeve can simply beurged inwardly of the container until the inlet holes have cleared theorifice when molten metal flows through the inlet holes into thesleeve-and along the axial bore of the sleeve.

The invention therefore avoids the use of a stopper and therefore doesnot embody the known disadvantages of stopper constructions and byavoiding the pro vision of a well in the ladle bottom, eliminates thepossibility of freezing taking place in the vicinity of the sleeve andconsequently there is no possibility of the sleeve sticking. Also,because the orifice closes the inlet holes any molten metal lying withinthe inlet holes and the axial bore drains out of the sleeve andaccordinglythere is no part of the means of the invention where moltenmetal can freeze, the invention therefore avoiding that disadvantage inknown slide valve arrangements.

To prevent flow of metal through the gap between the outside of thesleeve and the inside of the orifice that gap must be as small aspossible, i.e., the sleeve must be a close sliding fit in the orifice.To this end it is preferred that the sleeve and the part of the liningcontaining the orifice be of the same or different high qualityrefractory material, or ceramic material, such as silicon nitride orfused silica which have a very low and predictable expansion, andtherefore capable of providing and maintaining an accurate smoothsurface fihish to both the orifice and the sleeve.

Preferably, the orifice through the container is in an orifice block setin either the lower part of the container wall or the container bottom,and the orifice block may be located within a support block that may beintegral with or separate from the container lining. In either case theclosed end of the sleeve in its closed position is co-planar with thetop or inner face of the orifice block and the top or inner face of thesupport block. Preferably, the orifice block is held in place by amounting plate suitably secured to the container casing or shell, whichplate may also serve to hold the support block in place. It is furtherpreferred that the outer surface (s) of the orifice block tapers, and isset with its end of lesser diameter towards the inner face of thelining, the orifice block locating in a correspondingly shaped bore inthe lining or support block.

Movement of the sleeve may be effected by any suitable pneumatic,hydraulic, mechanical or electromechanical means, and may be a simplepush/pull action or the sleeve may be rotated as it is moved, the meanscausing movement being suitably secured to the container shell and thesleeve such that no excess stressing of the shell and sleeve, andparticularly bending moments applied to the sleeve, is caused. Thus, forexample, mechanical means may be provided in the form of a cradlepivotally secured on the mounting collar and with the ends of the armsof the cradle suitably secured to the exposed end of the sleeve wherebypivoting of the cradle causes the sleeve to be lifted and lowered, theconnection between the arms of the cradle and the sleeve being such thatno transverse loading is applied to the sleeve. Alternatively, two ormore hydraulic cylinders may be secured to the mounting collar and to aplate suitably secured to the exposed end of the sleeve.

Activation of the cylinders by the admission of pressure fluid causesthe sleeve to be moved inwardly and outwardly with respect to the vessellining to open and close the means of the invention.

The invention therefore provides an extremely simple and efficient meansfor controlling the flow of molten metal from a container free from theproblems of metal freezing with the consequent impairing of theperformance of the device. More than that it may be simply arranged toprovide a high degree of control of the rate of flow of molten metal.Thus, the inlet holes through the wall of the sleeve may be elongatewhen the degree to which they are exposed beyond the inner face of thecontainer lining dictates the rate of flow. Alternatively the inletholes may be circular and spaced along the sleeve such that progressivemovement inwardly of the sleeve first exposes one hole and then a secondand so on, again to determine the rate of the flow up to the maximumpermitted by the axial bore through the sleeve. It is preferred that theholes, whether elongate or plain cylindrical, should be inclined withrespect to the plain closed face of the sleeve.

The exposed end of the sleeve may be formed such that the axial boreextends directly to the end of the sleeve. Alternatively, the bore maybe caused to diverge towards that end of the sleeve, and branched toprovide a number of outlets.

It will also be recognised that a number of axial bores may be providedin the sleeve, each fed by a number of inlet holes, or that a number ofsleeves may be provided in a corresponding number of orifices in theorifice block.

One embodiment of the invention will now be described with reference tothe accompanying drawings, in which:

FIG. 1 is a perspective view of control means according to the inventionwith its mounting plate removed;

FIG. 2 is an underneath plan of FIG. 1 but shows the mounting plate;

FIG. 3 is a side elevation of FIG. 2 with the control means shownsecured to a ladle bottom;

FIG. 4 is a sectional side elevation of the device of FIG. 3; and

FIG. 5 corresponds to FIG. 4 but shows the control means in the open"position.

Means for controlling the flow of molten metal from a container such asa ladle 1 is formed by a sleeve 2 having an axial bore 3 open at itslower end and extending to two generally transverse, but downwardlyinclined, bores 4 emerging at the outside face of the sleeve 2 as inletholes 5 at points below the upper closed end of the sleeve. The diameterof each bore 4 is preferably equal to the diameter of the bore throughthe sleeve. The sleeve is mounted in a housing block 6 of high aluminaset in the bottom of the ladle and surrounding outlet hole from theladle, there being an orifice block or liner 7 set in the housing blockand in which the sleeve is a close sliding fit. Preferably, the orificeblock has an external downwardly divergent frustoconical shape to fit ina correspondingly shaped hole through the housing block. To prevent anymovement of the orifice block, the orifice block at its lower end isprovided with a collar 7A engaged by a correspondingly shaped lockingring 78. Therefore, any upward loading on the orifice block is taken bythe locking ring which, by being suitably secured to the lining,transmits such load to the lining and not to the housing block 6. Thelocking ring also serves to ensure that there is no transverse movementof the orifice block which might otherwise effect the movement of thesleeve.

The outside diameter of the sleeve is less than the inside diameter ofthe bore through the orifice block by an amount which, by virtue of thesurface tension of the molten metal, is less than that which would allowmolten metal to flow through the small gap between the two, but the gapbeing great enough to allow any expansion of both the sleeve and theorifice block without the sleeve jamming in the bore through the orificeblock. Thus, it is preferred to utilise silicon nitride as the materialfor both the sleeve and the orifice block which, by having a low andpredictable expansion allows a close machine fit between the two, orthey may be of fused silica which has a very low but predictablecoefficient of expansion. When utilising fused silica it is preferred tohave an overall tolerance between the diameters of the bore and thesleeve of between 0.002 and 0.003 inch.

The sleeve towards its lower end has a collar 8 secured between twoclamping rings 9 themselves held together by bolts 10. Secured toopposite sides of one (upper) clamping ring 9 is a locating lug 11, thelocating lugs being a sliding fit in a slot 12 in side support members13 secured to a valve mounting plate 14, the valve mounting plate beingsuitably secured to the ladle casing by welding or by bolts to serveadditionally to hold the orifice block in place. Also secured to thevalve mounting plate are two supports 15 for pivots 16 for a cradle 17,the outer ends of the arms of which lie alongside and outside thelocating lugs 11. The arms of the cradle are provided with slots 18towards their outer ends to receive clamp pivots 19 secured to thelocating lugs 11. The cradle 17 extends to an operating arm 20.

Thus, with the sleeve secured to the arms of the cradle, it is capableof movement between two positions, that shown in FIG. 4 when the top(closed) end of the sleeve is co-planar with the top or inner face ofthe orifice block, the support block and the ladle lining and theposition shown in FIG. 5 where the holes 5 are exposed to the inside ofthe ladle. With molten metal applied to the ladle with the closuredevice in the position shown in FIG. 4, molten metal is held within theladle and the ladle can be transported from a point alongside a furnaceto a position above a suitable receptacle (a mould) for the moltenmetal. During this time, the metal in the ladle forms no more than askull adjacent the face of the lining, there being no well inprotuberance which would increase the cooling effect on the metal withthe consequent danger of freezing. With the ladle in that position theoperating arm 20 is swung to cause the cradle to pivot about the pivots16, the engagement between the clamp pivots l9 and the slots 18 beingsuch as to cause the clamping rings 9 and thus the sleeve 2 to belifted. The engagement of the locating lugs 11 and the slots 12 in theside support members 13 ensures that the sleeve is maintained in avertical position during its movement. The slots 18 in the arms of thecradle 17 allow relative movement between the arms of the clamp pivots19 thereby preventing any transverse loading on the clamping rings 9.Thus, the sleeve 2 is lifted vertically until such time as the openingsto the inclined bores 4 lie above the top of the orifice block .7 whenmolten metal in the ladle is allowed to flow through the bores 4 and 3and into a suitable receptacle such as a mould. When teeming is to bediscontinued the arm is operated to cause opposite pivotal movement ofthe cradle 17 to lower the sleeve 2 until such time as the openings tothe bores 4 lie within the orifice block 7. Obviously, if teeming is notrequired to cease but is required to be reduced or throttled, the cradlecan be pivoted by an amount such that the sleeve 2 will be positionedwith the openings to the bores 4 lying partially within the orificeblock 7, the degree to which they lie below the top of the orifice blockdetermining the rate at which metal will flow through the bores.

To ensure that the top of the sleeve is co-planer with the top of theorifice block, in the closed position, set screws 21 are providedpassing through the bottom of the support members 13 and emerging in theslots 12 to be abutted by the locating lugs 11 in the lower (closed)position of the closure device. On closure of the device, any moltenmetal already in the bores 4 and 3 will continue to flow'out of thebores and accordingly, the device is self-draining. Due to the coolingeffect of the ladle lining, the so-called skull frequently forms abovethe closure device before teeming commences. However, the device is wellcapable of being lifted through the layer of viscous cooling metalforming the skull and the subsequent flow of hot metal is well capableof melting the skull.

Apart from the simplicity of the construction, one of the primaryadvantages of the device of the invention is that it gives a positionshut-off without the need for a stopper and without providing an areawhere molten metal can freeze, and the molten stream from the device iscompact and steady due to the effect of the relatively long bore 3 andis not subject to divergence from the outlet of the bore thereby givingbetter ingot quality on direct teeming. Also, because the sleeve can beinserted into the orifice from below, the sleeve itself can readily bereplaced should it be damaged during use without the need to dissemblethe other refractory components.

In addition to its applicability to direct teeming from' a ladle, thedevice may also be used to pour molten metal from tundishes incontinuous and sequential casting, and with the sleeve extended it canbe used for the submerged pouring of molten metals directly intocontinuous casting moulds. The device can also be fitted in the bottomof metal refining furnaces, e.g., electric arc and basic oxygen processfurnaces and used to teem molten metal from the furnace. It could alsobe fitted such that the sleeve is horizontally disposed and with thedevice mounted in the wall of a furnace at a predetermined level toprovide an outlet for slag or metal.

What we claim is:

1. Means for controlling the flow of molten metal from a container,comprising a sleeve located within an orifice in the container and meansadapted to move the sleeve relative to the orifice, the sleeve beingclosed at its end towards the inside of the container and open at itsopposite end and there being one or more inlet holes in the wall of thesleeve at a point approaching the closed end of the sleeve communicatingwith an axial bore through the sleeve, the sleeve being such as to becapable of insertion into the orifice from outside the container, andthe relative movement between the sleeve and the orifice being such asto move the sleeve from a first position in which the closed end of thesleeve is co-planar with the inside face of the part of the containercontaining the orifice, with the inlet holes lying within and beingclosed by the orifice, to a second position where the inlet holes areexposed to the inside of the container.

2. Means for controlling the flow of molten metal as in claim 1, whereinthe orifice through the container is in an orifice block set in eitherthelower part of the container wall or the container bottom, the closedend of the sleeve in its first position being coplanar with the innerface of the orifice block.

3. Means for controlling the flow of molten metal as in claim 2, whereinthe orifice block is located within a support block, the inner face ofthe orifice and support blocks being co-planar.

4. Means for controlling the flow of molten metal as in claim 3, whereinthe orifice block is of frusto-conical form with its end of lesserdiameter towards the inner face of the'lining of the container, theorifice block locating in a correspondingly shaped bore in the supportblock.

5. Means for controlling the flow of molten metal as in claim 2, whereinthe sleeve and the orifice block are formed from the same or differenthigh quality refractory material or ceramic material.

6. Means for controlling the flow of molten metal as in claim 5, whereinthe refractory material is silicon nitride.

7. Means for controlling the flow of molten metal as in claim 5, whereinthe refractory material is fused silica.

8. Means for controlling the flow of molten metal as in claim 2, whereina mounting plate is secured to-the ladle below the orifice block.

9. Means for controlling the flow of molten metal as in claim 1, whereinthe sleeve is moved relative to the orifice by a simple push/pull actionmeans.

10. Means for controlling the flow of molten metal as in claim 9,wherein mechanical means for moving the sleeve relative to the orificecomprise a cradle pivotally secured on the mounting plate and with theends of the arms of the cradle suitably secured to the exposed end ofthe sleeve whereby pivoting of the cradle causes the sleeve to be liftedand lowered, the connection between the arms of the cradle and thesleeve being such that no transverse loading is applied to the sleeve.

1 1. Means for controlling the flow of molten metal as in claim 10,wherein the lower end of the sleeve is 'se cured in a clamping ringprovided with locating lugs to engage in slots in side support memberssecured on the mounting plate, there being clamp pivots extendingfromthe locating lugs which pivots engage in slots in the ends of thearms of the cradle.

12. Means for controlling the flow of molten metal as in claim 1,wherein the inlet holes through the wall of the sleeve are elongate andthe degree to which they are exposed between the inner face of thecontainer lining dictates the rate of flow of molten metal through theaxial bore of the sleeve.

13. Means for controlling the flow of molten metal as in claim 1,wherein the inlet holes through the wall of the sleeve are circular andspaced along the sleeve such that progressive movement inwardly of thesleeve first exposes one hole and then subsequent holes to determine therate of flow of molten metal through the axial bore through the sleeve.

14. Means for controlling the flow of molten metal as in claim 1,wherein the inlet holes are inclined with respect to the plain closedface of the sleeve.

15. Means for controlling the flow of molten metal as in claim 1,wherein the axial bore through the sleeve extends directly to the end ofthe sleeve.

1. Means for controlling the flow of molten metal from a container,comprising a sleeve located within an orifice in the container and meansadapted to move the sleeve relative to the orifice, the sleeve beingclosed at its end towards the inside of the container and open at itsopposite end and there being one or more inlet holes in the wall of thesleeve at a point approaching the closed end of the sleeve communicatingwith an axial bore through the sleeve, the sleeve being such as to becapable of insertion into the orifice from outside the container, andthe relative movement between the sleeve and the orifice being such asto move the sleeve from a first position in which the closed end of thesleeve is co-planar with the inside face of the part of the containercontaining the orifice, with the inlet holes lying within and beingclosed by the orifice, to a second position where the inlet holes areexposed to the inside of the container.
 2. Means for controlling theflow of molten metal as in claim 1, wherein the orifice through thecontainer is in an orifice block set in either the lower part of thecontainer wall or the container bottom, the closed end of the sleeve inits first position being coplanar with the inner face of the orificeblock.
 3. Means for controlling the flow of molten metal as in claim 2,wherein the orifice block is located within a support block, the innerface of the orifice and support blocks being co-planar.
 4. Means forcontrolling the flow of molten metal as in claim 3, wherein the orificeblock is of frusto-conical form with its end of lesser diameter towardsthe inner face of the lining of the container, the orifice blocklocating in a correspondingly shaped bore in the support block.
 5. Meansfor controlling the flow of molten metal as in claim 2, wherein thesleeve and the orifice block are formed from the same or different highquality refractory material or ceramic material.
 6. Means forcontrolling the flow of molten metal as in claim 5, wherein therefractory material is silicon nitride.
 7. Means for controlling theflow of molten metal as in claim 5, wherein the refractory material isfused silica.
 8. Means for controlling the flow of molten metal as inclaim 2, wherein a mounting plate is secured to the ladle below theorifice block.
 9. Means for controlling the flow of molten metal as inclaim 1, wherein the sleeve is moved relative to the orifice by a simplepush/pull action means.
 10. Means for controlling the flow of moltenmetal as in claim 9, wherein mechanical means for moving the sleeverelative to the orifice comprise a cradle pivotally secured on themounting plate and with the ends of the arms of the cradle suitablysecured to the exposed end of the sleeve whereby pivoting of the cradlecauses the sleeve to be lifted and lowered, the connection between thearms of the cradle and the sleeve being such that no transverse loadingis applied to the sleeve.
 11. Means for controlling the flow of moltenmetal as in claim 10, wherein the lower end of the sleeve is secured ina clamping ring provided with locating lugs to engage in slots in sidesupport members secured on the mounting plate, there being clamp pivotsextending from the locating lugs which pivots engage in slots in theends of the arms of the cradle.
 12. Means for controlling the flow ofmolten metal as in claim 1, wherein the inlet holes through the wall ofthe sleeve are elongate and the degree to which they are exposed betweenthe inner face of the container lining dictates the rate of flow ofmolten metal through the axial bore of the sleeve.
 13. Means forcontrolling the flow of molten metal as in claim 1, wherein the inletholes through the wall of the sleeve are circular and spaced along thesleeve such that progressive movement inwardly of the sleeve firstexposes one hole and then subsequent holes to determine the rate of flowof molten metal through the axial bore through the sleeve.
 14. Means forcontrolling the flow of molten metal as in claim 1, wherein the inletholes are inclined with respect to the plain closed face of the sleeve.15. Means for controlling the flow of molten metal as in claim 1,wherein the axial bore through the sleeve extends directly to the end ofthe sleeve.